Mechanistic research:Selenium regulates virulence factors,reducing adhesion ability and inflammatory damage of Helicobacter pylori

BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host.Although selenium is closely related to pathogenicity as an environmental factor,the specific correlation between them remains unclear.AIM To investigate how selenium acts on virulence factors and reduces their toxicity.METHODS H.pylori strains were induced by sodium selenite.The expression of cytotoxin-associated protein A(CagA)and vacuolating cytotoxin gene A(VacA)was determined by quantitative PCR and Western blotting.Transcriptomics was used to analyze CagA,CagM,CagE,Cag1,Cag3,and CagT.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction,and H.pylori colonization,inflammatory reactions,and the cell adhesion ability of H.pylori were assessed.RESULTS CagA and VacA expression was upregulated at first and then downregulated in the H.pylori strains after sodium selenite treatment.Their expression was significantly and steadily downregulated after the 5th cycle(10 d).Transcriptome analysis revealed that sodium selenite altered the levels affect H.pylori virulence factors such as CagA,CagM,CagE,Cag1,Cag3,and CagT.Of these factors,CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite.Moreover,CagT expression was upregulated before the 3rd cycle(6 d)and significantly downregulated after the 5th cycle.Cag1 and Cag3 expression was upregulated and downregulated,respectively,but no significant change was observed by the 5th cycle.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction.The extent of H.pylori colonization in the stomach increased;however,sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H.pylori-infected mice,and the cell adhesion ability of H.pylori was significantly weakened.CONCLUSION These results demonstrate that H.pylori displayed virulence attenuation after the 10th d of sodium selenite treatment.Sodium selenite is a low toxicity compound with strong stability that can reduce the cell adhesion ability of H.pylori,thus mitigating the inflammatory damage to the gastric mucosa.

Application of traditional Chinese medicine in treatment of Helicobacter pylori infection

Helicobacter pylori(H.pylori)has a high rate of infection and antibiotic resistance and poses a serious threat to human life.One of the main strategies to overcome drug resistance is to develop new treatment plans.Traditional Chinese medicine(TCM)that is commonly used to treat many diseases in China can reduce drug resistance and increase the eradication rate of H.pylori.In this paper,we review the research progress on TCM in the treatment of H.pylori infection.The mechanism of action of TCM is reviewed and research and applications of TCM in the treatment of H.pylori are demonstrated.Finally,we discuss problems confronting the use of TCM for the treatment of H.pylori infection and propose possible solutions.In addition,the plans of TCM in H.pylori treatment were also screened:Dampness-heat syndrome in the spleen and stomach,deficiency of spleen and stomach,and cold-heat complicated syndrome,and the effective components therein are studied.The antibacterial effect of TCM is relatively slow;for rapid improvement of the treatment effect of refractory H.pylori gastritis,we provide an appropriate treatment regime combining TCM and Western medicine with immune-regulatory and synergistic antibacterial effects.

Treatment strategies and preventive methods for drug-resistant Helicobacter pylori infection

The infection and drug resistance rates of Helicobacter pylori(H.pylori)are high and must be prevented and treated by better strategies.Based on recent research advances in this field as well as the results from our team and those on traditional Chinese medicine,we review the causes of drug resistance,and prevention and treatment strategies for drug-resistant H.pylori infection,with an aim to make suggestions for the development of new drugs,such as establishment of new target identification and screening systems,modification of existing drug structures,use of new technologies,application of natural products,and using a commercial compound library.This article may provide reference for eradication of drug-resistant H.pylori.

Early genetic diagnosis of clarithromycin resistance in Helicobacter pylori

BACKGROUND The drug resistance rate of clinical Helicobacter pylori(H.pylori)isolates has increased.However,the mechanism of drug resistance remains unclear.In this study,drug-resistant H.pylori strains were isolated from different areas and different populations of Chinese for genomic analysis.AIM To investigate drug-resistant genes in H.pylori and find the genes for the early diagnosis of clarithromycin resistance.METHODS Three drug-resistant H.pylori strains were isolated from patients with gastritis in Bama County,China.Minimal inhibitory concentrations of clarithromycin,metronidazole,and levofloxacin were determined and complete genome sequencing was performed with annotation.Hp1181 and hp1184 genes were found in these strains and then detected by reverse transcription polymerase chain reaction.The relationships between hp1181 or hp1184 and clarithromycin resistance were ascertained with gene mutant and drug-resistant strains.The homology of the strains with hp26695 was assessed through complete genome detection and identification.Differences in genome sequences,gene quantity,and gene characteristics were detected amongst the three strains.Prediction and analysis of the function of drug-resistant genes indicated that the RNA expression of hp1181 and hp1184 increased in the three strains,which was the same in the artificially induced clarithromycin-resistant bacteria.After gene knockout,the drug sensitivity of the strains was assessed.RESULTS The strains showing a high degree of homology with hp26695,hp1181,and hp1184 genes were found in these strains;the expression of the genes hp1184 and hp1181 was associated with clarithromycin resistance.CONCLUSION Hp1181 and hp1184 mutations may be the earliest and most persistent response to clarithromycin resistance,and they may be the potential target genes for the diagnosis,prevention,and treatment of clarithromycin resistance.CONCLUSION Hp1181 and hp1184 mutations may be the earliest and most persistent response to clarithromycin resistance,and they may be the potential target genes for the diagnosis,prevention,and treatment of clarithromycin resistance.

Research progress in monitoring and simulating stem radius growth:an overview

Traditional dendroclimatology research is based on the statistical correlation between tree-ring chronology and modem observation data, but lacks consideration of the mechanisms of tree-ring growth. In order to reconstruct past climatic conditions more reliably, the response of stem radius growth dynamics should be studied in detail. At present, in intemational researches, monitoring and simulation methods are generally treated as two separate approaches. The monitoring method generally consists of dendrometer measurements, micro-coring, and pinning. Here, we present the research progress of stem radius growth dynamics studies derived from these methods, and provide prospects for future study.

Dinitride-free Li plating/stripping via lithiophilic seeds in a 3D matrix for enhanced Li-metal battery stability

The uncontrolled dendrite growth and volume change of Li metal during cycling lead to a short cycle life and safety concerns for Li-metal batteries,which hinders their practical application.Herein,we report the facile and energy-saving production of a three-dimensional(3D)CuZn matrix decorated with in-situ formed ZnO nano seeds(ZnO NS@3D CuZn)in pores and tunnels,which can serve as an anode current collector for dendrite-free Li-metal batteries.The 3D porous framework reduced the anode current density and accommodated Li volume change during the charge/discharge process.More importantly,the lithiophilic ZnO nano seeds induced fast Li deposition into the pores and tunnels of the 3D structure to effectively confine the deposited Li.As a positive effect,the volume change and Li dendrite growth during cycling are greatly suppressed.The half-cell with the ZnO NS@3D CuZn current collector exhibited a Coulombic efficiency(CE)of above 98%for over 320 and 240 cycles at 0.5 and 1 mA·cm^(-2),respectively.The Li@ZnO NS@3D CuZn symmetric cell achieves a lifespan of over 1500 h.Moreover,the Li@ZnO NS@3D CuZn||LiFePO4 full cell achieves a superb average CE of 99.4%and a long life of 600 cycles before the capacity retention rate decays to 90%.

Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CE

Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the available proxy archives. Here, we use 106 wood anatomical thin sections from 23forest sites and 20 tree species in both hemispheres to search for cell-level fingerprints of ephemeral summer cooling between 530 and 550 CE. After cross-dating and double-staining, we identified 89Blue Rings(lack of cell wall lignification), nine Frost Rings(cell deformation and collapse), and 93Light Rings(reduced cell wall thickening) in the Northern Hemisphere. Our network reveals evidence for the strongest temperature depression between mid-July and early-August 536 CE across North America and Eurasia, whereas more localised cold spells occurred in the summers of 532, 540–43, and548 CE. The lack of anatomical signatures in the austral trees suggests limited incursion of stratospheric volcanic aerosol into the Southern Hemisphere extra-tropics, that any forcing was mitigated by atmosphere-ocean dynamical responses and/or concentrated outside the growing season, or a combination of factors. Our findings demonstrate the advantage of wood anatomical investigations over traditional dendrochronological measurements, provide a benchmark for Earth system models, support cross-disciplinary studies into the entanglements of climate and history, and question the relevance of global climate averages.

Tree-ring-based winter temperature reconstruction for East Asia over the past 700 years

Almost all proxy-based temperature reconstructions for East Asia have hitherto been designed to resolve summer or annual temperature variability.Reconstruction for the winter temperature is still lacking.Here,we report an annually resolved,winter-season(December-February,DJF)temperature field reconstruction for East Asia covering the period 1300-2000 CE,based on 260 temperature-sensitive tree-ring records.The most striking feature of our new reconstruction is a significant longterm warming trend since the 14th century,which is associated with winter solar insolation at mid-latitudes of the Northern Hemisphere and the global anthropogenic impact.The amplitude of reconstructed winter temperature change over the study period was~4.7 times greater than that for summer temperature,and the rate of winter temperature increase was~6 times as much as that of summer temperature.The results from climate model simulations were consistent with the reconstruction,showing that the amplitude and rate of temperature change in winter were greater than those in summer.The reconstruction also suggests the possible influence of volcanic eruptions,anthropogenic activities and winter solar insolation on the winter temperature variations.Our result also suggests a long-term decrease in summer-to-winter temperature difference occurred in 1625(±24 years)CE.